And that -- this thread has now spilled over from Syria in -- eleven onto. And a stunning new number tonight from the United Nations more than half of the entire population of Syria now on the run. Now -- it's more than three million people have -- that country. Many of them children and look at this tonight our cameras are right there David Muir and our team on the Syrian border. Where children don't -- school -- big Ford pickup trucks taken to work in the field supporting their families at 8910. Years old. They come from middle class families their parents once teachers lawyers. And now they are the ones supporting their parents much more of David's reporting and the sliver of hope he discovered. Next week on world news tonight with David --

This transcript has been automatically generated and may not be 100% accurate.

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